Coating apparatus for applying a resin in particulate form



G. G. SIMPSON COATING APPARATUS FOR APPLYING June 22, 1954 A RESIN INPARTICULATE FORM 2 Sheets-Sheet 1 Filed Dec. 4, 1950 INVENTOR GEORGE G.SIMPSON ATTQRNEY June 1954 e. G. SIMPSON 2,681,637

COATING APPARATUS FOR APPLYING A RESIN IN PARTICULATE FORM 2Sheets-Sheet 2 Filed Dec. 4, 1950 INVENTOR GEORGE G. S/MPSON B & M)

ATTORNEY Patented June 22, 1954 COATING APPARATUS FOR APPLYING A RESININ PARTICULATE FORM George G. Simpson, Laurel, Miss., assignor toMasonite Corporation, Laurel, Miss., a corporation of DelawareApplication December 4, 1950, Serial No. 199,048

2 Claims. (Cl. 118-308) This invention relates to the application ofmaterials to surfaces, and more particularly to a coating apparatus foruniformly applying discrete solid particles, e. g. resins and the like,to the surface of sheet materials.

An object of this invention is an apparatus for applying discrete solidparticles to surfaces. A further object is a coating apparatus foruniformly applying discrete solid particles, e. g. resins, to thesurface of sheet materials. Yet a further object is an apparatus forapplying these particles to the surface of sheet material and fusingthem into a uniform film for coating the surfaces of sheet material suchas hardboard and the like. Other objects will be apparent from thefollowing description.

The above and other objects are accomplished according to this inventionbroadly by providing and employing an apparatus comprising a cylindricalcasing with its axis horizontally disposed and the chamber within thecasing closed at both ends and opened at the top and bottom, a feedsupply means attached to the casing over the top opening, a feeddiffuser means fed through the bottom opening, a shaft axially journaledin the ends of the casing, bristles which radiate from said shaft to thewalls of said chamber and to the feed diffuser so as to provide a rotarybrush for expelling theparticles which will make up the coating, meansfor driving said brush and means for conveying the material to becoated. Preferably the coating apparatus includes means, e. g. an airhammer, for vibrating the casing containing the brush. If the coatingmaterial applied is to be heated or fused, means for supplying heat isalso provided.

A preferred embodiment of this invention will now be described in moredetail with reference to the accompanying drawings which form a part ofthis application. Like reference numerals are used to indicate likeparts.

Referring to the drawings generally:

Fig. 1 isa side elevation. in. partial section showing an apparatusembodying the general aspects of the invention. I j Fig. 2 is a crosssection view along the line 22 of Fig. 1 showing the cylindrical casing,the rotary brush therein, the feed diffuser screen beneath the chamber,and the sheet material in position for being coated.

Fig. 3 is a cross section view along the line 3-3 of Fig. 1 showing theburners for fusing the coating material and the sheet material, andindicating the coating which has been. applied and fused on the sheet,and also showing the means for conveying the sheet material, and

Fig. 4 is a cross section of a modified form of support for the diffuserscreen. i

The cylindrical casing l of sheet metal or the like is arranged with itsaxis horizontal, and is preferably of length substantially equal to thewidth of the surface to be coated and extends transversely thereof. Thechamber la in the casing is closed at its ends 2. The casing is providedwith a top inlet opening 3 and a. bottom outlet opening 4. Theseopenings are of about the same length as the casing. An air hammer orhammers 5 vibrates the casing l and prevents caking or bridging of theresin particles. A feed hopper 6 supplies coating material to thechamber l a through opening 3 and has an adjustable feed regulatingshutter I in its throat. A feed diffuser screen 8 is disposed across theopening 4 and the particles of coating material are delivered throughthe openings of the screen on to the sheet being coated. The deliverythereof is effected and controlled by a rotary brush comprising theshaft 9 and bristles I0 whose points contact and engage the screen 8.The rotary brush will have drive means (not shown), e. g. an electricmotor preferably with speed control. A chute l5 conveys any spillage ofthe particles of coating material to the col lecting receptacle I6.

The heating means H, e. g. a bank of gas burners, beneath which thesheet with particles of coating material thereon is passed fuses theoriginally discrete particles l2 on to the surface of the sheet materialI 3, forming an adherent film or coat [3a thereon. Conduit I1, header l8and aspirators l9 supply gaseous fuel for heating the radiants 20.Conduit 2| supplies compressed air to the air hammers 5.

The coating apparatus is supported by the table 22 having legs 23.Conveying means, e. g. driven table rolls I 4, convey the sheet materialI3 to be coated beneath and beyond the feed diffuser 8 as indicated byarrow on Fig. 1. After leaving the conveyor comprising the rolls II, thesheet material carrying the resin particles is passed beneath theradiants 20 or other heat source by means of a metal heat-resistingconveyor comprising sprockets 24 and chain 25 from which the coatedsheets are delivered. Both conveyors are flat and level to prevent theboards or sheets getting out of level.

As shown in Fig. 4 the screen 8 may be attached removably andreplaceably to casing I as by securing it to a framepiece 8a andattaching such part Ba to the casing by screws 8b. When the particlesize of resin is changed the feed screen with corresponding. sizeopenings can thus be used. To support the screen from beneath, crossbars 80 can be provided at suitably spaced intervals. The framepiece 8aconsists of parallel angle-shaped members which extend across the widthof the cylindrical casing I, The opposed faces of the angle-shapedmembers extend downwardly from the feed diffuser 8 and serve to guide orrestrict the flow of the discrete resin particles and to direct themover a limited area of the sheet material to becoated.

In starting the coating apparatus the conveyor table rolls l4 and the.sprocket chain 25 are started, the gas burners H are ignited, the hopingthe adjustment stage the resin used passes into the chute i and isrecovered in receptacle it: for reuse. After the starting adjustmentshave been made and the desired temperature has been reached byadjustment'of the gaseous fuel supply, hardboards i3 are placed on the"conveyor table rolls: i l with the ends of the boards abutting eachother. These rolls convey the boards beneath the casing i. The bristlesforce resin particles through the feed diffuser screen 8, and to improvethe forcing action the shaft 9 may be made vertically adjustable tocompensate for wear of the bristle tips. The particles of resin fallonto the top surface of the boards, forming a remarkably uniform layerover the entire surface area of the boards. The boards with theirsupernatant layer of resin particles pass under the gas burners iadjacent to the resin applying apparatus. The heat from the burnersfuses the resin andcauses its particles to coalesce and adhere to thesurface of the boards in, the form of a continuous and very uniformfilm. Shortly after passing from beneath the burners, the filmisnon-tacky.

The thus coated boards may be used as a finished product at this pointif only a sing-le'ply having a protective film is desired. If it isdesired tc form a laminated product,.the coated boards may be laminatedimmediately (e. g. in a hot press) or they may be stored any length oftime desired before laminating. If both surfaces of. the boards are tobe coated, they may be run through the coating apparatus a second timewith the uncoated surface up.

A remarkable feature of this invention is the high degree of uniformityof the coating applied. This especially important in coating sheets tobe laminated in order to give a uniformly strong bond and to prevent thepossibility of uneven moisture content in the sheets resulting from theI 7 heat driving off moisture from thinly coated areas during fusion ofthe coating material, or from the evaporation or migration of moistureduring hot pressing of the coated sheets into a laminated product.

While details of the invention have been disclosed above in showing thepreferred construction and operation of the apparatus, modificaregulator1 renders a single hopper adaptable for use with many types of coatingmaterials. In some coating operations it is not desired to heat thecoating material applied. In such case, of course, heating elements arenot used. If heat is needed other sources besides gas may be used.

While Tampico bristles (vegetable fiber bristles) have given very goodresults, animal bristles, metallic bristles, synthetic bristles andother types of fiber bristles are applicable. Although the screen ofwire mesh 8 works well as a feed diffuser, any suitable perforatedmember may be employed.

The circumferential speed of the bristles, the linear speed of thematerial being coated, the type discrete solid particles used as 'acoating material, the temperature employed in. heating the coatingmaterial, the amount of coating material applied, the particular typeand mesh size of. the feed diffuser screen, and other variables may beregulated, varied or modified as desired. These and other regulationsand modifications are withinthe' skill. of the artisan.

Although this invention been described in detail with reference tocoating hardboards, it is applicable to applying coating materials tothe surfaces of materials in'general, such as e. g. veneers, lumber,metal sheets, paper.

It is to be understood that the invention is not to be limited tospecific embodiments thereof except as defined in the claims.

' I claim:

1. A coating apparatus for applying a resin in the form of discretesolid particles uniformly on the surface. of a sheet material whichcomprises a horizontally disposed cylindrical casing having a chambertherein closed at both ends and open at the top and bottom, means forvibratin the casing, a hopper for feeding the resin to the-containerattached to the casing over the' top openmg, means attached to thethroat of the hopper for regulating the feed of resin to the chamber, afeed diffuser screen fitted into the bottom casmg opening and attachedto the casing by means of parallelv angle-shaped members with theopposed faces of said angle-shaped members forming downwardly extendingguide members for the discrete resin particles, a shaft axiallyjournaled in the chamber, bristles which radiate from said shaft tocontact the feed diffuser, the tips of said bristles forming anessentially continuous pethe form of discrete solid particlesuniformlyon the surface of a sheet material which comprises ahorizontally disposed cylindricalv casinghaving a chamber therein closedat both endsrand open at the top and bottom, an air hammer for vibratingthecasing, a hopper for feeding the resin to the container attached tothe casing over the top opening, means attached to the throat of thehopper for regulating the feed of resin to the chamber, a feed diffuserscreen fitted into the bottom casin opening and attached to the casingby means of parallel angle shaped members with the opposed faces of saidangle-shaped members forming downwardly extending guide members for thediscrete resin particles, a shaft axially journaled in the chamber,bristles which radiatefrom said shaft to contact the feed diffuser, thetips of said bristles forming an essentially continuous peripherysubstantially coex- 15 2'557'561 tensive with the inner surface of saidcylindrical casing, means for driving said shaft, and means forconveying the sheet material being coated.

References Cited in the file of this patent UNITED STATES PA'IENTSNumber Name Date 465,815 Claus Dec. 22, 1891 841,685 Harris Jan. 22,1907 1,659,179 Wilson Feb. 14, 1928 1,904,591 Wilson Apr. 18, 19332,112,759 Boyer Mar. 29, 1938 2,211,435 Peterson Aug. 13, 1940 PowersJune 19, 1951

